Since showing it next to an empty chunk looks bad

Issue #4492

It sometimes produces invalid output.

Closes #4410

So that their vertical offsets actually match the position of the
corresponding lines.

Issue #4364

And use it in the merge addon to get the proper offsets for merge buttons

Issue #4364

Issue #4353

Issue #4353

Closes #4353

Issue #4288

Issue #4112

Closes #3802

Closes #3802

Since collapsing might move previously hidden code into the viewport

Issue #3599

Issue #3593

Closes #3549

Since the library is completely oblivious to module loaders

Issue #3447

Closes #2858

To prevent scrolling artifacts

...  for getting information about collapsed spans

See http://discuss.codemirror.net/t/jittering-mousewheel-scrolling-with-merge-addon-align-mode/125

Using the collapseIdentical option.

Closes #2783

Closes #2754

Bumping them for every release just adds too much git
noise and history blowup.

Issue #2529

Issue #2438

Issue #2438

Issue #2334